Chapter 16: Dynamic Routing Protocols
STANDARD Revision 1.0
C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved.
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Consequently, the underlying network protocol can be either IPv4 or IPv6. It is also possible to have two sessions between
two peers concurrently, one over IPv4 and one over IPv6.
The network layer transport protocol is important because it will determine the type of network layer transport address or
source address the BGP speaker will use (IPv4 or IPv6). When a route is originally advertised by a BGP speaker, the
NEXT_HOP attribute (or the next hop field in the MP_REACH_NLRI attribute) is set, by default, to the BGP speaker’s
network layer transport address. Thus, when the transport network layer address is an IPv4 address, the NEXT_HOP will
have to be an IPv4 address. Similarly, if the BGP source address is IPv6, then the NEXT_HOP will have to be an IPv6 address.
MP-BGP Implementation
The C4/c CMTS previously only supported BGP for IPv4 only. Starting in Release 8.2.5, the C4/c CMTS will support BGP for
IPv6 by implementing MP-BGP. The following points summarize MP-BGP implementation:
Multi Protocol BGP (MP-BGP) is originally defined in RFC 2283
MP-BGP is a framework that extends the original IPv4 BGP to be able to carry other address families.
MP-BGP introduces the concept of Address Family Indicators (AFI) and Sub-address Family Indicator (SAFI)
Some of the address families MP-BGP supports is:
IPv4 (AFI=1) --> Unicast (SAFI=1), Multicast (SAFI=2), VPNv4 (SAFI=128)
IPv6 (AFI=2) --> Unicast (SAFI=1), Multicast (SAFI=2), VPNv6 (SAFI=128)
Release 1.1 will support two address families:
AFI=1, SAFI=1 and AFI=2, SAFI=1
MP-BGP for IPv6 is used the same way we use BGP for IPv4
All addresses involved are IPv6
Router-ID for MP-BGP (IPv4 or IPv6) in default VRF only
The C4/c CMTS can be configured to run:
MP-BGP for IPv4 only
MP-BGP for IPv6 only
MP-BGP for IPv4 and IPv6
IPv4 routes will be advertised using MP-BGP for IPv4 only (not using IPv6 BGP Neighbor)
IPv6 routes will be advertised using MP-BGP for IPv6 only (not using IPv4 BGP Neighbor)
MP-BGP uses same message types as BGP